Caliper rule



March 24, 11%@ M. @A9-mom CALIPER RULE Filed May 8, 1,954

| l r l l z 1 1 1 s i l f @L T Patented Mar. 24, 1936 UNITED STATES PATENT GFFICE 4 Claims.

My invention relates to a caliper rule and has for its principal object, the provision of a relatively simple, practical and eicient device that may be conveniently used for performing the functions of a rule and calipers for obtaining direct readings of sixteenths, thirty-seconds and sixty-fourths of an inch in printed figures that appear one at a time in a window-like opening in the face of the tool while the same is being used.

In the use of an ordinary or standard scale or rule for taking measurements, there is to the average person more or less difculty in accurately reading the sixteenth, thirty-seconds and sixtyfourths of an inch, due to the multiplicity of the lines on the rule and the reading or the fine lines involves eye strain and waste of time and mistakes are very easily made.

To overcome these disadvantages, I propose to provide a relatively simple and practical device that is a combination of a rule and calipers and which device may be easily and quickly used with michrometer-like accuracy and precision in effecting measurements that involve graduations of a scale up to sixty-fourths of an inch, although if desired it is possible to utilize the same principal for higher graduations.

A further object of my invention is, tc provide a device of the character referred to, wherein a disc is rotated by the longitudinal movement of a bar through the body of the device and which disc carries on its face a plurality of concentrically arranged graduated scales and the graduations of which scales appear in succession through a window-like opening that is formed 'm the body of the device so as to give an accurate reading of the movement of the sliding bar or the distance between a head on the outer end of the sliding bar and the adjacent end of the body of the device while the same is being used in caliper operations.

With the foregoing and other objects in view my invention consists in certain novel features of rconstruction and arrangements of parts that will be hereinafter more fully described and claimed and illustrated in the accompanying drawing in which:

Fig. l is a front elevational view of a caliper rule constructed in accordance with my invention.

Fig. 2 is a front elevational View of the caliper rule with parts broken away and in section.

Fig. 3 is a vertical cross section taken on the line 3 3 of Fig. 2.

Fig. 4 is a cross section taken on the line 4-4 of Fig. 2.

Fig. 5 is an elevational view of the face of the disc that bears the graduated scales.

Fig. 6 is an enlarged detail section taken on the line 6-6 of Fig. 2.

Referring by numerals to the accompanying drawing which illustrate a preferred embodiment of my invention, I designates an elongated substantially rectangular body preferably formed of light weight cast metal such as aluminum and said body being provided adjacent to its lefthand end and on its rear surface with a circular chamber II and a smaller concentric chamber I2.

Applied to the rear face of body I 0 and suitably secured thereto, preferably by means of rivets I3, is a thin plate I4, preferably of metal that covers the chambers Il and I2.

Formed in the lower portion of the front face of the body ID, is a longitudinally disposed dovetail groove I and arranged for slight movement therein, is a bar I6, bearing on its front face a graduated scale.

Formed integral with or fixed to the left-hand end of bar I6, is a head I 'I, the inner edge of which is straight, and adapted to fit against the lefthand end of body I0 while the device is not in use.

The lower edge and the lower outer corner of the head II is knurled or corrugated as designated by I8 in order to be firmly engaged by the thumb when said head and bar are manipulated while taking measurements.

The front face of bar I5 is provided with a conventional graduated scale to show inches and divisions thereof.

The upper and lower edges of bar I6 are beveled for engagement with the beveled edges of the groove I5.

Suitably secured to the rear face of bar I6, preferably by means of rivets, is a rack bar I9 that occupies the rear portion of groove I5 and formed in the upper edge of said rack bar is a series of teeth that are cut with a 48 pitch gear cutter and there being exactly I6 teeth to the inch.

Projecting from the front wall of body I0, within chamber I2, is a stud I0, upon which is journaled a small gear wheel or pinion 2I. This pinion or gear wheel has I6 teeth cut with a 48 pitch gear cutter.

The teeth of this gear Wheel or pinion mesh with the teeth on the upper edge of rack bar I9.

The teeth on the rack bar do not extend all the way to the end of the bar opposite the end that is positioned adjacent to head II and thus the blank or uncut upper edge of the rack bar at the right hand end thereof provides a stop against which the teeth of the pinion engage to limit the outward movement of bar I 6 and rack bar I9.

Suitably secured to the rear face of gear wheel or pinion 2l, is a disc 22, preferably formed of thin metal which occupies the chamber II in body I0.

Appearing on the front face of disc l22, adjacent its edge, is a graduated scale suitably numbered to indicate sixty-fourths of an inch and just inside this graduated scale is a second concentric graduated scale divided and numbered to indicate thirty-seconds of an inch. Inside the last mentioned scale is a third concentric graduated scale bearing numbers to indicate sixteenths of an inch.

Formed through the upper portion of the front wall of body l, directly above the chamber l2 and pinion 2|, is an opening 23 having beveled side and lower edges that forms a window whereby the graduations and markings of the scales on disc 22 may be readily observed. If desired a thin section of glass or other transparent material may be located in this opening.

Appearing on the front face of the body I0 and intersecting the opening 23 and the groove l5, is a guideline 24 that insures accuracy in reading the numbered graduations on the disc 22 and the front face of bar I6.

A set screw 25 is seated in the front face of the lower lefthand portion of body l0, which set screw carries a ber disc 26 and the edge of the latter overlies the lower edge of bar I6 so that when the set screw is tightened said bar will be held against longitudinal movement in the body` In the use of my improved caliper rule, the head l1 on the end of bar I6 may be engaged by the thumb or linger and moved outward in order that the piece of material to be measured may be positioned between the head Il and the adjacent end of the body. Y

The head is now moved inward so that the work is engaged by the right hand edge of body l0 'and the inner edge of head il and the user of the tool now obtains an accurate reading of the diameter of the piece of material or other object by noting the scale graduation numbers that appear through the window 23 in alignment with the guide line 24.

In the operation of the device, it will be understood that as bar I6 and head I1 are moved longitudinally relative to the body, the teeth 20 on the upper edge of rack bar I9 engage and impart rotary motion to gear wheel or pinion 2| and to the disc 22 that is carried by said gear wheel and pinion and the face of which disc bears the graduated scales.

The number and pitch of the teeth on lthe pinion are such that said pinion and the disc carried thereby make one complete revolution for each one inch movement of the bars I6 and I9 and thus the device may be conveniently employed for accurately performing all caliper operations to obtain the width, thickness or diameter of objects or material positioned between the lefthand end of the body and the head l'l.

While the device is not in use, the sliding bars It and I9 and head are retained against longitudinal movement relative to the body I0 by means of the set screw 25, which when tightened exerts suflicient pressure against bar I6 to hold same against longitudinal movement.

My improved caliper rule comprises relatively few parts, is very compact, may be conveniently manipulated by one hand and by the arrangement of the three concentric graduated scales on the rotating disc, the graduated marks and numbers of said scales may be very easily read through the window without strain on the eyes and minimizing the possibility of making mistakes in reading the graduations.

Thus it will be seen that I have provided a caliper rule that is relatively simple in construction, inexpensive of manufacture and very effective in performing the functions for which it is intended.

It will be understood that minor changes in the size, form and constructionY of thevvarious parts of my improved caliper rule may be made and substituted for those herein shown and described without departing from the spirit of my invention, the scope of which is set forth in the appended claims.

I claim as my invention:

1. In a caliper rule, a body provided in its front face with a longitudinally disposed groove, the edges of which are beveled inwardly, a bar arranged for sliding movement in said groove, the edges of which bar are beveled so as to engage the beveled edges of said groove, a head carried by one end of said sliding bar, a', separately formed rack bar secured to the rear face of said sliding bar and occupying the rear portion of the groove in the body said body being provided with a pair of chambers of diierent sizes and having communication with each other, a pinion mounted for rotation within the smaller chamber, the teeth of which pinion engage the teeth of said rack bar, a disc carried by said pinion and occupying the larger chamber within this said body, the face of which disc bears a graduated scale and said body provided with a Window that communicates with the larger chamber in said body through which window the graduations of the scale on said disc are visible.

2. In a caliper rule, a body provided with a pair of chambers of different sizes, said chambers having communication with each other, there being an opening formed in the body above the smaller chamber therein, which opening communicates with the larger chamber in said body, said body being provided in its front face with a longitudinally disposed groove that `communicates with the small chamber in the body, a bar arranged for sliding movement in said groove, a head carried by one end of said bar, a rack bar secured to the rear face of said sliding bar and occupying the rear portion of the groove in said body, a pinion mounted for rotation within the smaller chamber in the body,V the teeth of which pinion engage the teeth of said rack bar, a disc carried by said pinion and positioned within the larger chamber in the body and the Y face of which disc bears a graduated scale that is visible through the opening in said body.

3. In a caliper rule, a body provided with a pair of chambers of diierent sizes, said charnbers having communication with each other,

there being an opening formed in the body above Y the smaller chamber therein, which opening communicates with the larger chambers in said body, said body being provided in its front face with a longitudinally disposed groove that communicates with the small chamber in the body, a bar arranged for sliding movement in said groove, a head carried by one end of said bar, a rack bar secured to the rear face of said sliding bar and occupying the rear portion of the groove in said body, a pinion mounted for rotation within the smaller chamber in the body, the teeth of which pinion engage the teeth of said rack bar, a disc carried by said pinion and positioned within the larger chamber in the body, the face of which disc bears a graduated scale that is visible through the opening in said body and means seated in the body for locking the sliding bar to said body in differently adjusted positions.

4. In a caliper rule, an elongated rectangular body provided in its front face with a longitudinally disposed groove, the edges of Which are beveled so as to engage the beveled edges of the groove, a head carried by one end of said sliding bar, the length of which body and the groove therein are such that the sliding bar is Wholly contained Within the body when the head on the end of the bar is positioned directly against the end of the body, a separately formed rack bar secured to the inner face of the sliding bar, said body being provided with a pair of chambers of different sizes and with an opening that communicates with the larger chamber in the body, a pinion mounted for rotation on the body and occupying the smaller one of the chambers therein, a disc carried by said pinion and occupying the larger one of the chambers in the body and the face of which disc bears a graduated scale that is visible through the opening in said body.

FRITZ MAX GAMROTH. 

